Life cycle energy and environmental analysis of a model biorefinery in Thailand

Abstract

This study aims to evaluate life cycle energy and environmental impacts associated with the production of biofuel (bioethanol) and biopolymer (polylactic acid, PLA) by using sugarcane and cassava as feedstocks for a possible model biorefinery in Thailand. Since there is currently no biorefinery in the country, secondary data sources from existing bioethanol and PLA plants were used for life cycle analysis (LCA). The system boundary was defined as cradle-to-gate and LCA methodology based on ISO 14040 series was used. Data were analyzed by using commercial LCA software, SimaPro 7.1, with Eco-Indicator 95 and CML 2 baseline 2000. The biorefinery processes was modeled and its performance was evaluated in several aspects such as fuel and biopolymer production, raw materials used, and total revenue generated for various scenarios. The results indicated that the biorefinery showed better performance in both global warming potential (GWP) and energy resources with increasing sugarcane usage. This was due to the use of bagasse and biogas as sources of fuel to generate electricity and steam by using cogeneration system in the biorefinery. In contrast, increasing PLA production led to higher GWP and energy resources impacts because of high electricity and steam usage in the bioplastic production process. Moreover, acidification potential (AP) and eutrophication potential (EP) impacts were also added in the results. Finally, eco-efficiency parameter was developed in order to combine both environmental (GWP, AP, EP, and energy resources) and economic (revenue) aspects by using average revenue gained and average impact associated. Among 5 scenarios studied, the results showed that S4 was the best scenario as it has higher eco-efficiency in several aspects.